Method and apparatus for enhancing wireless data network telephony, including quality of service monitoring and control

ABSTRACT

A system for wireless communication comprises an architecture of routers connected to a network and having connected transceivers for wireless transmission and reception of data, and a plurality of hand-held communicators adapted for users to communicate with the network through the routers. The system is adapted to provide wireless Data Network Telephony (DNT), and the hand-held communicators execute Quality of Service (QoS) code adapted to prioritize DNT packet code over all non-DNT traffic, thereby preserving the real-time nature of the DNT code.

CROSS-REFERENCE TO RELATED DOCUMENTS

The present invention is a divisional application from patentapplication Ser. No. 09/069,221 filed Apr. 28, 1998, now U.S. Pat. No.6,078,566. The priority case is incorporated herein in it's entirety byreference.

FIELD OF THE INVENTION

The present invention is in the field of network communications,including Data Network Telephony (DNT), such as Internet ProtocolNetwork Telephony (IPNT) and pertains more particularly to methods andapparatus for enhancing DNT in narrow bandwidth wireless links.

BACKGROUND OF THE INVENTION

The art of telephony communication has grown in proportion with improvedtelephony infrastructure, equipment, and methods of practice.Conventionally and historically telephone communication has beenpracticed by use of networks that provide dedicated connections andguaranteed bandwidth, such as in Publicly Switched Telephony Networks(PSTN). In such networks a call placed from a telephone connected to alocal service is switched over dedicated channels to a destination, andas long as the connection is maintained, the dedicated path, having adedicated bandwidth, is also maintained. Such networks may be termedConnection Oriented/Switched Telephony (COST) networks, and this term isused in this specification.

More recently, with the development of extensive data networks, of whichthe well-known Internet is a prime example, a newer type of telephonycommunication has been introduced. This form of telephony is termedherein Data Network Telephony (DNT), and, in the context of the Internetdata network Internet Protocol Network Telephony (IPNT). Data networkstypically link computers over one or more sub-nets, which may includelocal area networks (LAN), wide area networks (WAN) such as theInternet, company Intranets, and combinations of these and other datanetworks.

In DNT, such as IPNT, dedicated connections are not provided except inrare and special instances. Instead, digital audio data is prepared instandardized audio packets complete with header information and thelike. The packets are prepared in near real-time and broadcast over thedata network(s) connecting involved computers adapted for DNTapplications. The header for each packet includes a destination for thepacket.

Data Network Telephony, such as IPNT is well-known-in the art, andwireless data transmission is also quite well-known in manyapplications. Internet service providers, for example, are recentlyproviding high data-rate wireless Internet access by satellite systems,and, where bandwidth is not substantially restricted at the receiver'send, such systems have proven successful for WEB page delivery and thelike. Such systems have not proved to be friendly for DNT applications,and there are a number of reasons, which apply to these kinds of systemsand to other kinds of wireless systems of more limited bandwidth evenmore so.

The problems for Data Network Telephony in wireless systems are relatedto the real-time nature of telephony data and the typically limitedbandwidth available in such systems. In relatively high-bandwidthsystems having a relatively large number of users the distributionprobabilities provide a situation where it is uncommon for several ormany users to demand unusual bandwidth at the same time. The phenomenonis known in the art as averaging. Even with known high-use times, it canbe expected that distribution will be such that bandwidth will beadequate. In most wireless systems however, bandwidth is more precious,and averaging is hence not as helpful.

A contributing problem is in the nature of real-time audio data asopposed to data transmitting stored documents and the like, which may becalled data-data as opposed to voice-data. Data-data is prepared inpackets for transmission from stored data of known capacity. The numberof data packets needed to transmit a stored document, whether text,graphic, audio, or other, is a known quantity. Moreover, there is nofundamental loss if such data becomes delayed in transit. Once itarrives at a destination, the document may be reproduced.

Voice-data packets for real-time conversations are different. Thepackets for voice-data have to be prepared and transmitted inessentially real time in both directions or a meaningful conversationcannot be held. Moreover, the magnitude of packaged voice-data for aconversation will be inflated by acoustical background noise, whichunder some conditions can double or triple or even further multiply theamount of data having to be sent, imposing severe demand on availablebandwidth.

The inventor has carefully considered the possibilities of a number oftypes of potential DNT applications, and has determined that it isdesirable to provide DNT in wireless systems of many sorts to takeadvantage of some of the inherent advantages of DNT over dedicatedconnection-type telephony systems, and to provide DNT capability insystems that also are capable of data transfer of the data-data typedescribed above, such as of stored digital documents and entities. Anovel system in this patent application is proposed, for example, usingrelatively small, battery-powered, hand-held computer communicators withDNT capability to be carried by users within range of multiple NetworkInterface Adapters (satellite transceivers). In a preferred embodimentwireless communication is provided by RF signaling. The invention,however, is not limited to RF, and could be implemented in an Infrasystem or any other system providing wireless communication.

In such a system the Network Interface Adapters may be coupled, forexample, to a Local Area Network. Such a system would be quite useful ona company premises for workers to keep in touch, hold phoneconversations, share documents locally (Campus Intranet), andcommunicate with the Internet and other connected computers as well(Inter Campus Intranets or Extranets). Many variations of such systemsare possible, but present technology does not render such systems reallypractical. Methods and apparatus according to various embodiments andaspects of the present invention, taught in enabling detail below,provide substantial improvements rendering such voice/data systems onnarrow bandwidth links quite feasible and useful.

SUMMARY OF THE INVENTION

In a preferred embodiment of the present invention a data networktelephony (DNT) system is provided, comprising a base station connectedto a DNT-capable data network and to a wireless transceiver and adaptedto operate the transceiver by a two-way, narrow-band, multiple-channel,real-time duplex radio protocol, and to process DNT calls on theDNT-capable data network and to broadcast and receive the DNT calls toand from the plurality of communicator units via the transceiver as DNTdata packets; and a plurality of portable computer-enhanced communicatorunits, including microphone and speaker apparatus, each adapted tocommunicate with the base station by the two-way real-time radioprotocol and to process DNT calls. The portable, computer-enhancedcommunicator units are adapted to prioritize DNT data over other datawhen transmitting on the wireless network, such that DNT data always isprocessed before non-DNT data.

In one embodiment the DNT-capable data network is a local area network(LAN).

In some embodiments one or more of the communicator units is equippedwith Digital Signal Processors (DSPs) adapted for recognizing humanspeech, and wherein audio data for DNT calls is processed by the DSPs,allowing substantially only human speech to be prepared as DNT packetsfor transmission. In other embodiments one or more of the communicatorunits is equipped with noise cancellation microphone and speakerapparatus adapted for creating a noise reduction zone in the region of aprinciple speech input microphone.

In another aspect, in a system providing wireless communication betweena portable communication unit and a base station over a dedicatedchannel, wherein the portable device is adapted for Data NetworkTelephony (DNT), a method is provided for enhancing quality of DNTcalls, comprising steps of (a) monitoring all outgoing wireless trafficat the portable communication unit; (b) recognizing DNT data as opposedto non-DNT data; and (c) transmitting DNT data always with preferenceover non-DNT data. In this method, in some embodiments the portablecommunication unit comprises a CPU and a memory, and the method isprovided by the CPU executing a Quality of Service (QoS) algorithmstored in the memory. In other embodiments the method is provided by theCPU executing Quality of Service (QoS) code provided a s a portion of anoperating system (OS) or a BIOS.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is an architectural overview of a wireless DNT system accordingto an embodiment of the present invention.

FIG. 2 is a system diagram of the components and connectivity ofcomponents within a hand-held DNT device and associated network elementsaccording to an embodiment of the present invention.

FIG. 3A is a block diagram illustrating DSP function according to anembodiment of the present invention.

FIG. 3B is a perspective view of unit 100 of FIG. 1 showing speaker andmicrophone placement.

FIG. 4 is a conceptual diagram illustrating QoS components andnegotiation according to an embodiment of the present invention.

FIG. 5 is a block diagram illustrating dynamic address translationaccording to an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is an architectural overview of a wireless DNT voice-data system99 according to one embodiment of the present invention. Wirelessvoice/data system 99 comprises a plurality of receiving/sendinghand-held units 100-600 that may be carried and used by individualsmobile throughout a local area such as a corporate campus having severalbuildings, and so on. System 99 in various embodiments is aradio-frequency (RF) based communication system, and may be atime-division-duplex multiple access (TDMA) system, a code-divisionmultiple access (CDMA) system, or any other type two-way wirelessprotocol system, all of which are well-known in the art or may beinvented in the future, but that are essentially wireless systems.

In other embodiments, voice/data system 99 may operate via infrared orother known or future form of wireless communication. Radio frequencysystems are used in this embodiment for illustration because of theirflexibility and abundance in the art. In some situations a combinationof wireless technology may be used such as RF in combination withinfrared capability with the infrared capability attributed toperipheral devices that may be used with a system.

Each hand-held unit 100-600 (there may be more or fewer) is of the formof a portable computer and communication device such as a palm-topcomputer. Such devices are known in the art and may be suitable forpractice of the present invention with addition of certain elementswhich will be clear from following descriptions. Each receiving/sendingunit communicates via RF, as previously described, and has an RFinterface module such as interface module 109 that is capable ofreceiving and sending radio signals and has a network interfacecapability.

Each unit 100-600 has appropriate computer functionality attributed topalm-top and other portable style computers, and is powered, in mostembodiments, via rechargeable battery. In some embodiments whereportability is not an issue, they may be powered electrically via wallsocket adapters as well, with recharge capability for battery packs.However, in a preferred embodiment unit 100 is portable. It will beapparent to the skilled artisan that many more units as allowed byavailable bandwidth may be used within a voice/data system 99.

Each unit 100-600 is capable of communicating in RF mode with asatellite transceiver 400 that may be located in a convenient proximity(communication range) to the sum of portable units within a sub-net ofsystem 99. Satellite transceiver 400 is dedicated to broadcasting andreceiving data in RF mode to and from each unit such as unit 100-600 andhas appropriate interface capability for computer communication as wellas radio frequency sending and receiving capability. Satellitetransceiver 400 is linked via dedicated digital connection 401 to arouter 410 in the embodiment shown. This link may be any one of manysorts, such as serial pair, optical link, and so on.

Router 410 is, more specifically, a digital routing node, adapted forrouting data packets as in a digital network like the Internet. However,in some specialized embodiments wherein calls are received from atelephone network such as the Public Switch Telephone Network (PSTN) aswell as from a digital network, a router encompassing both types oftelephony capabilities may be used. A router with dual capability (i.e.routing both PSTN calls that are converted to DNT calls and originallysourced DNT calls) is known to the inventor.

Router 410 is linked via digital network connection to a network 500.Network 500 may be of the form of a local area network (LAN), a widearea network (WAN), the Internet, an Intranet, or another type of publicor private digital network known in the art. Router 410 may be furtherlinked as illustrated via dedicated connections 411, and 412 to otherrouters or transceivers (not shown) as would be the case with amulti-distributed system wherein voice/data systems such as system 99are duplicated and distributed over a larger geographical area (i.e. acampus) and linked to a network such as network 500. Dedicatedconnections 411 and 412 are identical in scope to connection 401 aspreviously described.

In an exemplary system according to the invention, each transceiver,such as transceiver 400, communicates with users over 16 dedicatednarrow-bandwidth channels. There may be, in some instances, more than 16units 100-600 in a transceiver area and assigned to users and atransceiver channel. In some cases, a channel may be shared by two ormore infrequent users while a frequent user may have a dedicatedchannel. In embodiments of system 99 having multiple transceivers, userswith communication devices roam from system to system as will bedescribed further below.

According to a preferred embodiment of the present invention, DNT suchas IPNT may be practiced by a user operating a portable communicationdevice such as unit 100 while connected in wireless mode to a voice/datasystem such as system 99, enabling the user to actively send and receivereal-time data associated with DNT as well as to perform other datatasks such as file downloading, uploading and the like without losingthe quality of the real-time DNT communication. Such a user may alsoroam away from and out of range of system 99, in a multi-distributedembodiment, wherein any real-time data that was sent but not received bythe user as he or she moves between transceiver regions is immediatelyrerouted as the user is associated with a new satellite transceiver.This feature allows a user to be completely mobile during real-time datatransfer.

As previously described with reference to the background section, DNT isnot currently practical when practiced on networks having narrowdedicated bandwidth such as TDMA or CDMA systems as compared to highbandwidth systems (i.e. satellite wireless and connection-orientedsystems) wherein sufficient bandwidth for DNT and other data transfercan be assured by packet averaging techniques and so on. Therefore, itis an object of the invention to provide method and apparatus forenabling successful and economical practice of DNT including IPNT overwireless networks of the prevalently existing narrow-bandwidth typedescribed above. Such method and apparatus of the present invention isdetailed in various embodiments below.

FIG. 2 is a system diagram of the components and connectivity ofcomponents within voice/data unit 100 of FIG. 1, and associated networkelements external to unit 100 according to an embodiment of the presentinvention. Voice/data hand-held unit 100 is shown in FIG. 2 as a blockdiagram to reveal various components and features, some of which areenabling to unique features of the present invention, and some of whichare standard features available in current art and generic to suchdevices.

Unit 100 has a central processing unit (CPU) 101 in this embodimentincluding a digital signal processor (DSP) 101 a. In some embodiments,DSP 101 a may be separate from CPU 101, such as a separate chipcommunicating on bus 113. DSP 101 a is adapted for voice recognition andmay discern human voice from background noise. DSP functionality asprovided in this embodiment is unique and is described in further detailbelow.

Because unit 100 is a portable computer as well as a DNT communicationdevice, suitable memory for storing programs and data is provided asmemory (MEM) 102 and non-volatile memory (NV MEM) 103.

A speech system 104 contains the necessary components for enabling DNTand IPNT telephony communication, and for doing necessary A/D and D/Aconversion between digital voice-data and analog voice signals from amicrophone (mic) or to operate a speaker. In this embodiment, amicrophone 106 and a speaker 105 are provided for audible send andreceive function. In some cases an additional noise cancellationmicrophone 106 b and a noise cancellation speaker 105 b are included forthe purpose of minimizing background noise. More detail regarding thisunique noise elimination technique as applied to an embodiment of thepresent invention is provided below.

An infrared tranceiver 107 is provided for the purpose of interfacingwith peripherals that communicate via infrared signal. Infraredtranseceiver 107 accepts input from such peripherals and converts thedata to digital form for bus 113. Of course any other type of wired(such as USB) or wireless desktop network could be employed, includingbut not limited to induction, RF and so forth. Data-data, as referencedin the background section, such as file documents and the like, may beconverted to infrared data and stored, executed, or printed oninfrared-capable peripherals that may be used with system 99.

A standard keyboard 112 and screen 110 are provided to unit 100 as withmost portable computers. The screen may be any of a broad variety ofsuch devices as known in the art. The keyboard may be a QWERTY keyboardor another sort. A mini-keyboard 111 may also adapt to unit 100 in someembodiments instead of keyboard 112 for the purpose of input foroperation of unit 100, for example mimicking a simple telephoneinterface. Similarly, peripheral devices such as a full size keyboard151 a PC 152 may communicate with unit 100 via infrared or other wiredor wireless link as previously described. RF interface 109 providesdigital wireless interface with transceiver 400.

It will be apparent to one with skill in the art that there may begeneric or new features inherent or known to the inventor to a palm-topor lap-top computer that are not described in detail in this embodiment.The inventor intends only to detail those aspects incorporated into unit100 that are relevant to operation of the present invention. Commonlyfound components such as screen 110 and keyboard 112 will not bedescribed with great detail because to do so may obscure the innovativeaspects of the present invention. More detail regarding the innovativeaspects according to embodiments of the present invention are providedbelow.

Improved Noise Reduction for DNT Application

In embodiments of the invention each satellite transceiver 400 in thesystem of FIG. 2 (there may be additional such tranceivers connected torouter 410, or to equivalent routers) typically broadcasts on a fixednumber of channels within an assigned frequency range over an areasurrounding the transceiver. Typically, each hand-held unit tunes to aparticular channel, which may be negotiated with router 410 or otherintelligence in the system. As a result there are typically a relativelysmall number of users in such a system in the range of one satellite,and each user is dealing with router 410 through transceiver 400 over avery “thin pipe”. By thin pipe in this specification is meant aconnection to a user via a channel with very limited bandwidth.

It appears to the present inventor that a major concern when practicingDNT over such a narrow-band thin pipe is noise reduction capability. Aspreviously described in the background section, background noiseseverely limits the bandwidth available, because as packets are preparedin substantially real time, packets must be prepared for backgroundnoise, even during long pauses in conversation. Bandwidth may thereforebe wasted that could profitably be used for other purposes, such asexchange of data-data or, depending on the wireless network, for sharingwith other users. The inventor proposes two approaches which may be usedseparately or may be combined to considerably reduce the waste ofbandwidth by background noise for DNT over a narrow-band pipe.

The first implementation involves the use of DSP (see DSP 101 a of FIG.2) technology with speech recognition capability, and is described andillustrated below.

FIG. 3A is a block diagram illustrating DSP function according to anembodiment of the present invention wherein only voice data packets andreal data packets are sent during a transaction with a calling or calledparty.

DSP technology, while known in the art and applicable to many differenttypes of products, is an innovative approach as it is applied to anembodiment of the present invention. The inventor knows of no currentnarrow-band wireless application wherein DSP with speech recognition isused for the purpose of managing bandwidth whereby only necessary datapackets for voice-data are created during a real time transaction suchas a DNT voice call. Data-data associated with file transfers and thelike are created normally and sent along with voice data. In someinstances, CPUs can be used to perform DSP tasks, and hence no extraphysical implementation of the DSP has to exist. Also, some newer DSPdesign lend themselves to handle general purpose CPU/MPU functions, andhence can handle all aspects by themselves.

Referring now to FIG. 3A, as a user speaks into a microphone during acall. DSP 101 a with speech recognition capability monitors input, sortsout speech from non-speech, and creates data packets for voice only andwill not create packets during pauses when the user is not speaking. Inthis way, bandwidth is made available for other functions because datapackets containing background noise and the like are never created.Data-data packets containing non-voice data such as file-transfer dataand the like are created in normal fashion and sent along with DNTpackets if the user is, of course, transferring a file and talking onthe unit at the same time. This technique in this embodiment assumesthat there is sufficient bandwidth for multi-task functions whileactively engaged in a DNT call.

The speech recognition function of the DSP chip may be programmed ortrained to recognize different languages and so on. Also long sighs andother verbal non-descriptors may be ignored during the monitoring andDNT packet generating process.

In another embodiment of the present invention, a DSP chip with speechrecognition capability is also provided in routers such as router 410.By using digital to analog conversion modules known in the art, incomingDNT packets, before encountering may be monitored by a similar DSP atrouter 410 and non-speech packets in a received DNT data stream can beeliminated, effectively making more efficient use of the narrowbandwidth of each channel to a user. DSP apparatus and techniques asdescribed can effectively minimize bandwidth demand for DNT in narrowwireless channels in either or both directions.

FIG. 3B is a perspective view of unit 100 of FIG. 1 showingnoise-cancellation speaker and microphone incorporation. While DSP withspeech recognition capability is effective in reducing unwantedbackground noise, it may not be 100 percent effective, therefore anothernoise reduction technique is used wherein possibly a second microphone106 b and possibly one more speaker 105 b are provided and strategicallylocated on unit 100 for the purpose of canceling background noise thatmay be present at the users location. Depending on the implementationand the physical design of the device, additional MIC/SPKR may or maynot be needed. If a system such as system 99 of FIG. 1 is implemented inan industrial-setting, for example, background noise may be particularlysignificant. Speaker 105 and microphone 106 are used for normal speechand audio function during a DNT call or may be used in combination fornoise cancellation.

It will be apparent to one with skill in the art that there may be morethan one noise-cancellation speaker 105 b as well as more than onenoise-cancellation microphone 106 b in unit 100 without departing fromthe spirit and scope of the present invention. The number and locationof such devices will depend in part on intended application. Forexample, in a quiet environment, they may not be needed at all, whereas,in a noisy environment maximum capability may be desired. In general,the noise cancellation system works by intercepting background noise bythe auxiliary mic (106 b), then playing background noise back throughone or more noise cancellation speakers placed to cancel backgound noisein a region at the principle mic 106. Such noise cancellation is knownin the art for such as traffic noise and the like, but application andimplementation to background noise reduction enhancing DNT over narrowwireless links is surely unique and not obvious

It will be apparent to one with skill in the art that cancellationspeakers and microphones may be held separate from unit 100 withoutdeparting from the spirit and scope of the present invention. Oneexample of this would be utilization of a noise cancellation head-set.

Pipe-Mirroring in a Narrow Band Wireless Multi-Access System

Attention is directed to FIG. 2, to hard wired link 401 betweenintelligent router 410 and transceiver 400. Router 410 is adapted toroute data packets for both voice-data in DNT and data-data for such asfile transfers to users in an area covered by transceiver 400. Typicallyeach user is assigned a channel within the breadth of the transceiverTherefore voice-data and data-data for each user occupies just thatchannel in the wireless link between transceiver 400 and each user'shand-held unit. The hardwired link 401 is, however, preferably a singleline, and carries all of the combined data for all the users in the areaof transceiver 400. This arrangement, however, can be troublesome, asrouter 410 sees only the combined bandwidth of all the channels.Therefore, in the event one or more of the users elects to download alarge amount of data, router 410 would typically command the entirebandwidth of hardwired link 401 to transfer the data to transceiver 400,and any or all DNT communications may be interrupted. In a preferredembodiment of the present invention, then, router 410 treats hardwiredlink 401 as though it were a link of the bandwidth of the wirelesschannel for each user, dividing the hardwired link into a number ofparallel pipes equal to the number of wireless channels used. Datamanagement between real time voice-data and data-data is thereforemaintained for the system between the router and the users, and DNT maybe effectively maintained for the individual users.

QoS Functionality on Ultra-thin Pipes

In a preferred embodiment of the present invention, in order to insurethat DNT data is prioritized when sending a combination of DNT data andapplication data via the narrow-band wireless channel for each client, abasic but innovative Quality of Service (QoS) scheme is implemented onthe client side.

Traditional bidirectional QoS application schemes such as resourcereservation protocol (RSVP) and similar schemes are known by thoseskilled in the art to be only used in high bandwidth applications wherethere are many users sharing available bandwidth. It is also well knownthat QoS assurance on both ends of a pipe has to be negotiated along theway from node to node. Also, QoS implementation across multiple networksis difficult. Some standardization is required so that all networkpoints understand and support the language protocol of the scheme beingused.

FIG. 4 is a conceptual diagram illustrating QoS management according toan embodiment of the present invention.

It is the intention of the inventor to provide a new, one-sided QoSimplementation from the clients side to the other end of the pipe,namely router 410. This is accomplished in embodiments of the inventioneither with firmware that is embedded in NV MEM 103, or via a softwareapplication 501 installed in system memory available in unit 100. Inthis embodiment, an instance of application 501 also resides in router410. The application provides a fixed algorithm that always prioritizesDNT data both in unit 100 and in router 410. In this way, DNT data, asreal time data, is always assured sufficient bandwidth. If another datatype such as data from file transfer is initiated while simultaneouslyengaging in a DNT call, all such packets are held until there is a pausein the speech wherein no DNT data is being transferred. The transferringof files initiated by unit 100 takes place only during data gaps in theprioritized DNT communication. This is a one directional feature thatonly effects the communication link between unit 100 and router 410, andthe instances of application 501 at each end operate independently ofthe other. In other embodiments the unique uni-directional QoS routinemay be used only at one end of the pipe or the other, either in router410 or in the user's hand-held unit.

Dynamic Address Translation

In yet another embodiment of the present invention, a method is providedwhereby a user may roam away from and out of range of a transceiver suchas transceiver 400, and be smoothly and efficiently logged onto anothertransceiver in system 99.

FIG. 5 is a block diagram illustrating dynamic address translationaccording to an embodiment of the present invention. Three transceiverregions 97, 98 and 99 are shown provided by separate transceivers spacedapart from each other but with overlapping areas, as is known in the artfor such wireless systems; as is done in cell-phone systems, forexample. Together, regions 97, 98, and 99 define a sub-net 404. Sub-net404 is, in this case, serviced by a single router 410. Such a case mayrepresent, for example, a technical campus. Each unit 100 is capable ofoperating on one or another of defined channels in each of regions97-99, and RF tuning in the hand-held units is a matter of apparatus andprocedures that are all well-known in the art.

Router 410 in this embodiment is a lower-level router in a multi-levelrouting system connected to a higher-level router 415 via link 413. Inthis embodiment router 415 is a Master router for the wireless system,and is linked to Net 500. Master router 415 may be linked as well toother lower-level routers such as router 417 in another subnet 405equivalent to subnet 404, which in turn controls three transceivers,such as transceiver 418.

It will be apparent to the skilled artisan that there is a broad varietyof architectures that might be implemented comprising routers inhierarchical levels, interconnection among routers, and connection ofrouters to transceivers to accomplish coverage of an area for such awireless communication system. The architecture illustrated here is oneof many possibilities, and is used for exemplary purposes to illustrateimproved tracking of users across subnets in an embodiment of thepresent invention.

Generally speaking, when incoming DNT calls arrive at master router 415,they are routed appropriately based on routing tables in the severalrouters. In the overall system, each user may have a home locationserved by a particular transceiver connected to a particular router. Aparticular user may, for example, typically be found in region 99 servedby transceiver 403 connected to router 410. This user will then belisted on the routing table of router 410 and the table of Master router415. If a call comes in to Master router 415 for this particular user,the call will be quickly routed to the proper end router and transceiverby virtue of the routing list entries. Each satellite transceiver suchas transceiver 403 has a fixed number of channels, and a channel isassigned to each user.

The purpose of a distributed system of the sort illustrated inembodiments of the present invention, is to provide communication forall users regardless of the particular region (transceiver), and toallow users to move from region to region while maintainingcommunication.

As an example, the user of unit 100, shown in FIG. 5 as resident inregion 99, has decided to roam to region 97 covered by transceiver 402.In the system of various embodiments, location negotiation isperiodically executed by each unit in operation with the nearesttransceiver. As long as a user does not move from one region to another,the routing tables do not change. As the user of unit 100 enters region97, negotiation communication will occur with both transceivers 403 and402. At some point the system will determine that the user is to behanded off to transceiver 402, at which time the routing tables areupdated, deleting the particular user from transceiver 403 and assigningthe user to transceiver 402.

Each hand-held unit tunes to the system-assigned channel, and unit 100will initially negotiate with router 410 through transceiver 402 on thesame channel that was assigned to the unit in region 99 served throughtransceiver 403. There may, however, be one or more users in region 97assigned to the same channel, and once the routing tables are updated,the channel assignment may change in the newly-entered region. Eachtransceiver, for example may have more channel capability than usersexpected at any one time to be in that region, and therefore may haveunused channels at any point in time that may be assignable to usersnewly entering the particular region.

In this example, router 410 services both regions 99 and 97 throughtransceivers 403 and 402 respectively, making this a relatively simpleexample of ripple. However, if the user of unit 100 were to roam tosubnet 405, where the transceivers are controlled by router 417, thenunit 100 would ping that new router through the closest satellitetransceiver, and negotiate entry into the new subnet. In this case theuser would be moved from the routing table in router 410 to the routingtable in router 417, rather than just updating the routing table inrouter 410 to a new transceiver and region.

In the process of rippling, users throughout the overall area covered bya wireless system are tracked, and their location relative to thenetwork of transceivers is noted. Routing lists at each router areupdated as users move from region to region in the manner describedabove, wherein the minimum change is made with minimum impact on thestored and updated data for the system.

When a user moves from region to region as has been described, androuting lists are updated, there will be instances wherein a user isreceiving real-time data packets for DNT as the user's location isupdated. At the time that the user is relisted in a new region, theremay well be data packets delivered to the router where the user waspreviously listed. In this instance real-time data packets, or for thatmatter any data packets, that are left behind in this manner, areretrieved and forwarded immediately to the router serving the region towhich the user has been moved, so there is no apparent loss in the datastream for the roaming user.

It will be apparent to the skilled artisan that there may be a varyingnumber of routers such as router 410 assigned a varying number ofsatellite transceivers without departing from the spirit and scope ofthe present invention. There may also be, in more sophisticated systems,several hierarchical levels of routers. There are many possibilities forsystem architecture.

Personal Router in Client

In yet another embodiment of the present invention, a softwareapplication known to the inventor as a personal router application isemployed for flexibility in routing. Complete and enabling detail forsuch a personal router system is taught in patent application Ser. No.08/869,815 assigned to the assignee of the present patent application.

In the personal router system a user, through an executable applicationat the hand-held unit, may, among other capabilities, programalternative actions for incoming calls. For example, a user may need toleave an area, and a co-worker is selected to cover the first user'sresponsibilities. In this case, the first user can program through thehand-held unit and the personal router application, for incoming callsto the first user to be re-routed to the alternate. A broad range ofother alternatives is available, including automatic answering withpre-recorded messages, call-holding, and many others. In a preferredembodiment a user interface is provided wherein incoming calls arerepresented by icons on the user's screen, which the user may select tomanipulate calls.

In one embodiment the bulk of the personal router application isresident at the system routers, and each user has an interface wherebyhe/she may access the application on the system router in aclient-server fashion, and edit routing rules on the router to effectthe manner in which incoming calls for the user are handled. The rulesthat may be invoked in this manner are limited only by systemcapabilities and the user's needs.

The personal router application provides maximum flexibility to the userwithout requiring additional equipment. A user need not be resident inany one voice/data system in order to apply his personal routing rules.By having an instance of the router application at each of the routersin the network, a user may roam without losing access to personalrouting capability. By utilizing a hierarchy of routers, personalrouting capability may be scaled up to cover a large geographical areasuch as routing calls to other sub-nets and so on.

It will be apparent to one with skill in the art that the personalrouting application may be used in conjunction with other routingapplications that may be implemented separately from individual unitswithout departing from the spirit and scope of the present invention.For example, as a DNT telephony application, routing software may bestored at a machine dedicated to interfacing with routers so that morecomplicated routing rules may be observed.

Practicing DNT Wireless Telephony on a CSMA/CD Type Network

All of the embodiments of the present invention as previously taughtherein are applicable to assigned the typical bandwidth types ofwireless networks such as TDMA and CDMA networks. However, successfulpractice of the present invention in various embodiments can be furtherenhanced by implementing a wireless protocol between transceivers andusers based on the characteristics of carrier-sensed multiple-accessnetworks including collision detection (CSMA/CD). This type of networkis most often employed as a hard-wired or wireless LAN architecture suchas Ethernet.

In CSMA/CD all data is transmitted over a shared channel and eachregistered device that attempts to transmit data on the network mustfirst listen to see if the network is free(carrier sense). Each devicehas a preset priority to use the available bandwidth over the network(multiple access). If two devices attempt to transmit at the same time,a collision occurs which is detected by all devices on the network(collision detection). Each device typically plans it's second-attempttransmission at a random amount of time after a collision is detected.As all of this takes place in a matter of micro-seconds, CSMA/CDprovides a means of efficiently utilizing available bandwidth in awireless shared system.

Bandwidth-on-demand means that no device transmits during thetransmission of another device on the network. Instead of individualchannels of dedicated bandwidth being assigned to each unit, allincoming DNT communications are broadcast over the network wherein eachunit picks up it's own coded information via addressing within thepacket frame.

CSMA/CD in wireless mode operates virtually the same as in hard-wiredmode except that the network architecture with respect to linked deviceswould be closer than would be the case with a wired network. Theinventor knows of no wireless CSMA/CD network that currently practicesDNT. For purposes of the present invention the wireless CSMA/CDimplementation could use existing wireless LAN technology with thereplacement of RF/NIA adapters such as module 109 of FIG. 1 withexisting LAN type network adapters.

It will be apparent to one with skill in the art that the methods andapparatus of the present invention as taught by the various presentedembodiments allows DNT including IPNT to be practiced efficiently andeconomically on a wireless narrow-band network having dedicated channelsas well as a wireless network having a shared channel with carrier sensecapability and collision detection capability without departing from thespirit and scope of the present invention. For example, the methods andapparatus of the present may be implemented in various networks such asTDMA, CDMA, Global System Mobile (GSM), and other similar networks aswell as CSMA/CD type networks.

It will also be apparent to one with skill in the art that such awireless network enhanced by methods and apparatus of the presentinvention may comprise a plurality of voice/data systems belonging toone of a plurality of sub-nets each controlled by a router with eachrouter linked to a LAN, a WAN, including but not limited to, theInternet. There are many other architectural possibilities with regardsto building such networks. The spirit and scope of the present inventionis limited only by the claims that follow.

What is claimed is:
 1. A data network telephony (DNT) system,comprising: a base station connected to a DNT-capable data network andto a wireless transceiver operating the transceiver by a two-way,narrow-band, multiple-channel, real-time duplex radio protocol, andprocessing DNT calls on the DNT-capable data network; a plurality ofportable computer-enhanced communicator units, including microphone andspeaker apparatus, each communicating with the base station by thetwo-way real-time radio protocol and processing DNT calls to and fromthe base station via the transceiver as DNT data packets; and aplurality of Digital Signal Processors (DSPs) operating in one or moreof the communicator units for recognizing human speech; characterized inthat the portable, computer-enhanced communicator units prioritize DNTdata over other data when transmitting on the wireless network, suchthat DNT data always is processed before non-DNT data, and furthercharacterized in that audio data for DNT calls is processed by the DSPs,allowing substantially only human speech to be prepared as DNT packetsfor transmission.
 2. The DNT system of claim 1 wherein the DNT-capabledata network is a local area network (LAN).
 3. The system of claim 1wherein one or more of the communicator units is equipped with noisecancellation microphone and speaker apparatus for creating a noisereduction zone in the region of a principle speech input microphone.